It is a known fact that on the average, fluorescent lights consume up to 75% less energy than incandescent lamps with the same light output. The EPA estimates that if Americans were to convert from incandescent lamps to fluorescent, the energy saved would be equivalent to removing one third of all automobiles from the road. Fluorescent lights also have substantially longer service lives, up to ten times the life span of incandescent bulbs, and new generations of highly efficient fluorescents with excellent color rendition are being produced in various compact shapes and sized all the time.
Fluorescents and other higher efficiency lamps, of which fluorescents are the cheapest and most efficient, cannot operate on bare household AC current but require a ballast and a starter to provide the optimum starting and operating voltages. A screw fluorescent conversion for an incandescent mount has all three on-board, sometimes having a replaceable fluorescent tube element. The starter and the ballast circuitry may be integrated, or the starter may be integral with the lamp.
Aside from the considerably higher initial cost, traditionally there are two hurdles to converting from incandescent to fluorescent fixtures. First, the fluorescent tube (discharge tube) produces a limited amount of light per linear unit of length, requiring it to be many times longer than the thickness of an incandescent bulb. This requires inventive folding and convoluting to even approach conforming to the same space requirements as incandescents. Some incandescent installations are still too confined to permit upgrading.
Second, the weight and bulk of the conventional magnetic, transformer-style ballast makes it difficult for fluorescents to compete in some installations with the light-weight, compact incandescent. Conventional ballasts have copper wire transformer coils which make it very heavy, in addition to being bulky. These limitations have made it difficult to provide a screw-in fluorescent fixture that could be used in a normal incandescent light bulb socket.
With the development of electronic ballasts, the weight and bulk limitations formerly dictated by the coiled wire magnetic ballasts has been partially eliminated. Besides the weight and overall volume restrictions of the ballast, magnetic ballasts also must be provided as a single mass since the coils must be as close as possible to one another for the most efficient transforming.
Ballast as a design limitation has largely disappeared as magnetic ballasts have given away to modern electronic ballasts. The new ballasts may be arranged and configured to accommodate more desirable spatial distributions conforming more closely to the shape of the space available. This is exemplified in the patent to this case, U.S. Pat. No. 5,471,375 issued Nov. 28, 1995. Also by the same inventor, U.S. Pat. No. 5,362,246 issued Nov. 8, 1994, discloses a compact fluorescent replacement with a special initial installation mode, and U.S. application Ser. No. 08/221,803 filed Apr. 1, 1994 disclosed a replacement system particularly useful to large scale installations, enabling hotel corridors and restaurants to upgrade without the usual high cost of completely ripping out the old mounting structure, and achieving true replacement with self-cooled fixtures, not the recessed "conversions" destined by design to burn out from overheating with a year or two.
In 1981, Thorn EMI lighting of the United Kingdom launched its 16 watt compact fluorescent lamp line called the "2D", named for its resemblance to two back-to-back D's. The 2D series has been developed from 1981 to the present to include different sizes and different power level fluorescent lamps, and is now owned by General Electric Lighting. The initial 16 watt lamp has been expanded to a line of three different base size configurations and five different wattage levels ranging from 10 watts to 38 watts for a total of five different lamps.
In addition to the variations in wattage rating and overall base configurations, two of the 2D lamps come in yet another variation which is identical to the original except that they incorporate the starter in the lamp base, and thus require only two pins to connect to a pin socket platform. These two pins are positioned at loci on the pin platform different from any of the four pins of the alternate configuration, without the starter, however. The lamps that do not include the starter have four-pin plug structure, so that there are altogether three different lamp configurations and two different pin platform configurations.
Currently there are two basic commercially available lamp mounting sockets. One is for all the 2-pin lamps, and the other is for the 4-pin lamps. The single 2-pin lamp mounting socket will receive either of the two available 2-pin lamp sizes, and the 4-pin socket, will receive either of the three available 4-pin lamp sizes. The lamp fixture, however, contains the ballast appropriate to only a single wattage. Therefore, with current lamp mounts there is the distinct possibility that lamps of incorrect wattage rating will be plugged into available lamp assembly mounts. Although there may be coincidental limitations on the available volume due to surrounding structure which would make impossible mistaken use of a large tube in a lamp mounting socket for a small tube, the converse would always be possible. The 10-watt unit will fit all of the other sizes, and would be either immediately burned out, or have a very limited life span, if inadvertently plugged into a 38-watt lamp mounting socket.
There is a need for a lamp assembly mount which is specifically tailored to the 2D lamp series and which manifests multiple improvements over the prior art lamp base assemblies in both weight and volume and eliminates the possibility of inadvertent power mismatches.